Chronic Laminitis: Understanding Lameness and Low-Dose Bute

Chronic Laminitis: Understanding Lameness and Low-Dose Bute

Hood noted rapid response (lameness improvement) in 30-50% of the study horses within the first 24 hours after Bute administration.

Photo: The Horse Staff

To treat any lameness issue a veterinarians must first identify the origins of pain and etiologies responsible--something that can be particularly challenging in a horse with laminitis. David Hood, DVM, PhD, of the Hoof Diagnostic and Rehabilitation Clinic (HDRC) in Bryan, Texas, shared some effective methods to pinpoint laminitic pain and explored using the non-steroidal anti-inflammatory (NSAID) phenylbutazone (Bute) to control it at the 6th International Equine Conference on Laminitis and Diseases of the Foot, held Oct. 28-31 in West Palm Beach, Fla.

Veterinarians often use differential nerve blocks to pinpoint pain's region of origin (e.g., solar, heel, fetlock, metacarpal, etc.). In a series of experiments using nerve blocks on chronically laminitic horses coupled with force plate evaluation of lameness severity, Hood noted the following results:

  • Not all lameness is a result of pain avoidance (Some "appear to be related to chronic elevation of the heels and/or contracture of the flexor tendons and suspensory apparatus," Hood explained.);
  • Most lameness originates in the solar and heel regions, rather than the laminar interface.
  • Nondigital lameness (such as due to degenerative joint disease higher up in the limb) frequently is superimposed on digital lameness; and
  • There is a high incidence of hind limb lameness in horses with chronic laminitis, attributed to "repeated overloading of the rear limbs in attempts to rise without fully loading the forefeet," said Hood. 

Hood also described an experimental study on Bute's pain-relieving effects in which he administered low-dose oral Bute to 20 laminitic horses 30 minutes before morning feeding, followed by performing a force plate-based stance analysis in the afternoon.

Hood noted rapid response (lameness improvement) in 30-50% of the horses within the first 24 hours. Their pain levels plateaued (stopped improving), however, after four to 10 days on this regimen. When treatment was discontinued after 10 days the horses all returned to their original levels of lameness within three to eight days.

Conclusions Hood drew from this study include:

  • Don't expect a rapid response with Bute administration, and don't elevate a horse's dosage until his pain levels have plateaued.
  • NSAIDs do not address pathologies associated with laminitis.
  • Owners should be forewarned of a delayed return to lameness in horses after Bute use has been discontinued.

About the Author

Alexandra Beckstett, The Horse Managing Editor

Alexandra Beckstett, Managing Editor of The Horse and a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as Assistant Editor of its book division, Eclipse Press, before joining The Horse.

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